Spring 源码中一些小工具
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2022-04-15 23:39:39
1. 包扫描方法,扫描指定包路径下的类org.springframework.context.annotation.ClassPathBeanDefinitionScanner#doScan在指定的基本包内执行扫描,返回注册的bean定义。核心扫描逻辑代码org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#scanCandidateComponents可以把这部分源码进......
1. 包扫描方法,扫描指定包路径下的类
org.springframework.context.annotation.ClassPathBeanDefinitionScanner#doScan
在指定的基本包内执行扫描,返回注册的bean定义。
核心扫描逻辑代码
org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#scanCandidateComponents
可以把这部分源码进行魔改 ,改写成一个工具类 扫描指定路径下的类,参考 componentScan注解的配置方法。
样例代码:
public class ClassScaner implements ResourceLoaderAware {
//保存过滤规则要排除的注解
private final List<TypeFilter> includeFilters = new LinkedList<TypeFilter>();
private final List<TypeFilter> excludeFilters = new LinkedList<TypeFilter>();
private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
private MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(this.resourcePatternResolver);
public static Set<Class> scan(String[] basePackages,
Class<? extends Annotation>... annotations) {
ClassScaner cs = new ClassScaner();
if (ArrayUtils.isNotEmpty(annotations)) {
for (Class anno : annotations) {
cs.addIncludeFilter(new AnnotationTypeFilter(anno));
}
}
Set<Class> classes = new HashSet<Class>();
for (String s : basePackages)
classes.addAll(cs.doScan(s));
return classes;
}
public static Set<Class> scan(String basePackages, Class<? extends Annotation>... annotations) {
return ClassScaner.scan(StringUtils.tokenizeToStringArray(basePackages, ",; \t\n"), annotations);
}
public final ResourceLoader getResourceLoader() {
return this.resourcePatternResolver;
}
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourcePatternResolver = ResourcePatternUtils
.getResourcePatternResolver(resourceLoader);
this.metadataReaderFactory = new CachingMetadataReaderFactory(
resourceLoader);
}
public void addIncludeFilter(TypeFilter includeFilter) {
this.includeFilters.add(includeFilter);
}
public void addExcludeFilter(TypeFilter excludeFilter) {
this.excludeFilters.add(0, excludeFilter);
}
public void resetFilters(boolean useDefaultFilters) {
this.includeFilters.clear();
this.excludeFilters.clear();
}
public Set<Class> doScan(String basePackage) {
Set<Class> classes = new HashSet<Class>();
try {
String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
+ org.springframework.util.ClassUtils
.convertClassNameToResourcePath(SystemPropertyUtils
.resolvePlaceholders(basePackage))
+ "/**/*.class";
Resource[] resources = this.resourcePatternResolver
.getResources(packageSearchPath);
for (int i = 0; i < resources.length; i++) {
Resource resource = resources[i];
if (resource.isReadable()) {
MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(resource);
if ((includeFilters.size() == 0 && excludeFilters.size() == 0)
|| matches(metadataReader)) {
try {
classes.add(Class.forName(metadataReader
.getClassMetadata().getClassName()));
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
}
} catch (IOException ex) {
throw new BeanDefinitionStoreException(
"I/O failure during classpath scanning", ex);
}
return classes;
}
protected boolean matches(MetadataReader metadataReader) throws IOException {
for (TypeFilter tf : this.excludeFilters) {
if (tf.match(metadataReader, this.metadataReaderFactory)) {
return false;
}
}
for (TypeFilter tf : this.includeFilters) {
if (tf.match(metadataReader, this.metadataReaderFactory)) {
return true;
} else {
return false;
}
}
return true;
}
public static void main(String[] args) {
ClassScaner.scan("com.onion.service", Service.class)
.forEach(clazz -> System.out.println(clazz));
}
}
2.获取当前默认的类加载器
使用 ClassUtils.getDefaultClassLoader()
本文地址:https://blog.csdn.net/oschina_40730821/article/details/107356688
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